1. Field of the Invention
The invention relates to a connector having an inner displacement member which prevents the flow of a liquid from a pouch into a hose system in a first state and which only allows the flow after displacement.
2. Description of the Related Art
It is known in the prior art to allow the flow from systems in sterile packaging through a hose only on application. In EP 0 038 355 A1, a break-off pin is located at the inside of the hose which is broken off to release the flow and should then wedge transversely in the hose. The disadvantage of this design is the possibility that minute breakage particles can enter the solution and thus the place of application, which causes unpleasant side effects for the patients, particularly with intra-peritoneal solutions or infusion solutions. Puncture membranes are also known which have the same disadvantages.
Inner displacement members in adapters are also known from EP 0 798 013 A1 where the displacement member is reversibly supported in the adapter. The displacement member is pushed back into the starting position over and over again without any external influence due to the resilient force of an inner spring. The design of such a displacement member is very complex and expensive to manufacture and therefore can not be used in disposable systems.
It is the object of the present invention to provide a disposable connector, preferably for connection to medical apparatuses, which is simple to manufacture at a low price and which prevents the flow in a first state and allows the flow after the irreversible switch into a second state. The object is solved by a connector having hose connections at the proximal end and the distal end, and having an inner displacement member which is movable in the axial direction of the connector. An inner lumen allows flow therethrough with at least one outlet aperture and at least one flow aperture which is impervious to flow in a first position. The inner displacement member has a stop in order to define a second fixed position at which at least one flow aperture is opened for flow.
Solutions, for example disinfecting solutions, infusion solutions orxe2x80x94during kidney substitute therapyxe2x80x94so-called dialysis solutions are often used in medical treatment systems. These solutions are preferably supplied in sterile packaging in containers or flexible pouches or they are manufactured on site in storage containers. The storage containers are connected to the treatment system via a connector so that the solution is available during treatment. It is of particular interest here that the connector is initially closed until the solution reaches the point of application in order then to be switched to an opened state. To prevent a premature accidental leaking of the solution, a manual opening by the operator should be avoided during normal handling.
For this reason, connectors or adapters have been developed, which are only opened manually after the connection or assembly of a hose system. The connector in accordance with the invention also belongs to this type, but has the advantage that the flow is opened simultaneously with the connection to the machine, whereas a seal against the environment is ensured beforehand. This effect is achieved by an inner piston which can be axially displaced exactly one time in a cylindrical housing by a corresponding counter-piece at the machine. On connection to the machine, an inner, displaceable piston is pushed into the front part of the connector and thus the flow aperture released for the passing through of fluid.
The connector is preferably made of plastic, particularly formed from two different plastic materials. While the outer connector part is made of polypropylene, in particular for connection to other polyolefin materials, the displaceable inner part should be made of silicone rubber. The whole connector is thus a disposable part, also in connection with the hose system, which can be made at low cost in an injection moulding process and in a simple design due to the simple assembly of the two components. The error-proneness is naturally also extremely reduced by the low number of components.
In addition to the simple handling for the user, which requires no additional hand movement such as breaking off a pin, screwing or turning, it is also reliably prevented that particles enter the continuing hose system.
Since no object lies in the continuing line in an undefined manner, the same flow is always ensured, as the inner piston is always pushed in to the same, identical position and releases the defined flow aperture thanks to its stop. The flow aperture can be formed by one or more lateral openings which are located in a first, closed state in a section of the connector which has such a narrow lumen that the flow apertures contact sealingly or lie upstream of this tapered position at which the displacement member sealingly contacts the inside of the connector. In a second, open state, the displacement member is pushed into a region of the connector which has a larger inner diameter. In this way, the flow apertures move into a region downstream of the tapered position and are released for the flow.